The utilization of a pair of gears or a pair of racks with offset teeth have been used to minimize backlash; however, devices of this type have been complicated. The present invention is directed to an anti-backlash means, particularly adapted for photographic enlargers, and a primary object is to provide an anti-backlash device having a minimal number of parts which may be readily molded, and readily installed.
A further object is to provide an anti-backlash device wherein a pair of rack elements are supported in a frame integral therewith, in such a manner as to have limited displacement so as to maintain pressure contact with an opposing drive gear and either the rack elements or the drive gear may be provided with offset teeth to prevent backlash.
A further object is to provide an anti-backlash rack and drive gear assembly wherein the drive gear is supported on tracks parallel to the racks by means of wheels having a diameter corresponding precisely to the pitch diameter of the drive gear.